Captopril, (S)-1-(3-merapto-2-methyl-1-oxopropyl)-L-proline, having the structural formula ##STR3## is an orally active angiotensin converting enzyme inhibitor useful for treating hypertension and congestive heart failure. See Ondetti et al. U.S. Pat. No. 4,105,776.
Enalapril, (S)-1-N-1-(ethoxycarbonyl)-3-phenypropyl!-L-alanyl!-L-proline, having the structural formula ##STR4## is also an orally active angiotensin converting enzyme inhibitor. Enalapril contains the L-alanyl-L-proline dipeptide. A related compound, lisinopril, also possesses oral angiotensin converting enzyme inhibitor activity and contains the L-lysyl-L-proline dipeptide. See Harris et al. U.S. Pat. No. 4,374,829.
Haslanger et al. in U.S. Pat. No. 4,749,688 disclose treating hypertension by administering neutral metalloendopeptidase inhibitors alone or in combination with atrial peptides or angiotensin converting enzyme inhibitors.
Neustadt in U.S. Pat. No. 5,075,302 disclose that mercaptoacyl aminolactams of the formula ##STR5## wherein Y includes propylene and butylene, R.sup.1 is lower alkyl, aryl or heteroaryl, and R.sup.2 is hydrogen, lower alkyl, lower alkoxy lower alkyl, aryl-lower alkyl or heteroaryl-lower alkyl are endopeptidase inhibitors. Neustadt disclose employing such compounds alone or in combination with angiotensin converting enzyme inhibitors to treat cardiovascular diseases such as hypertension, congestive heart failure, edema, and renal insufficiency.
Delaney et al. U.K. Patent 2,207,351 disclose that endopeptidase inhibitors produce diuresis and natriuresis and are useful alone or in combination with angiotensin converting enzyme inhibitors for the reduction of blood pressure. Delaney et al. include various mercapto and acylmercapto amino acids and dipeptides among their endopeptidase inhibiting compounds.
Flynn et al. in European Patent Application 481,522 disclose dual inhibitors of enkephalinase and angiotensin converting enzyme of the formulas ##STR6## wherein n is zero or one and Z is O, S, --NR.sub.6 -- or ##STR7## Additional tricyclic dual inhibitors are disclosed by Warshawsky et al. in European Patent Applications 534,363,534,396 and 534,492.